In 2011, Gyimah produced a report with the think-tank NESTA, "Beyond the Banks: the case for a British Industry and Enterprise Bond",[16] in support of non-bank alternatives for businesses seeking finance. He was the first member of parliament to call for credit-easing as a means of accelerating Britain's economic recovery.[17]

Gyimah was appointed as Parliamentary Private Secretary (PPS) to the Prime Minister at the 2012 reshuffle, then became a Government Whip in October 2013.[2]

On 20 November 2015, Gyimah contributed to the filibustering of the opposition-proposed Compulsory Emergency First Aid Education (State-Funded Secondary Schools) Bill to make the teaching of first aid in secondary schools compulsory. He spoke until the end of the debate, despite requests from the deputy speaker.[19]

On 21 October 2016, Gyimah filibustered the Sexual Offences (Pardons) bill (nicknamed the "Turing Bill" after Alan Turing), a private member's bill presented by the Scottish National Party MP John Nicolson that sought to pardon all men convicted of abolished offences under the sodomy laws, on the grounds that granting automatic pardons to all men convicted of historic ‘gay sex crimes’ would mean that some men who had raped and/or had sex with young men under the age of 16 would be pardoned.[20] Supporters of the bill disputed this, as they proposed conditions for a pardon which included the act being consensual and that it would not be contrary to present-day British law.[21][22][23] He instead supported an amendment proposed by the government to existing legislation, in which only dead men convicted of such offences were automatically pardoned, while those who were living would have to apply to the Home Office through a "disregard" process.[23][24] Gyimah has consistently voted in favour of LGBT equality, including the right of same-sex couples to marry.[25][better source needed]

As Minister for Universities, Science, Research and Innovation, Gyimah has warned that “there’s a culture of censorship in some of our universities" and that threats to freedom of speech were not "some right-wing conspiracy theory that had been made up". Some of the examples he has mentioned included a professor at King's College London who was allegedly reported for hate speech after teaching a history class, and a university's safe-space policy that took 20 minutes to read. In both cases, the universities in question reported that these things did not happen, and the Department for Education clarified later that Gyimah had merely relayed students' anecdotes.[26]

On 30 November 2018, Gyimah became the seventh government minister to resign over Theresa May's Brexit deal, which he called naive, saying "Britain will end up worse off, transformed from rule makers into rule takers. It is a democratic deficit and a loss of sovereignty". He called May's withdrawal agreement "a deal in name only" with many unresolved issues that would leave the UK at the mercy of the European Union with no leverage for many years to come.

He said the UK's weakness in the negotiations over the Galileo satellite navigation project was the final straw and he intended to vote against May's deal in the House of Commons on 11 December 2018, and suggested the public should have the right to a final say on the withdrawal agreement in another referendum with the Article 50 process extended.[27] Gyimah resigned as a minister because he wants to be free to endorse a second referendum on Brexit.[28] In early 2019, he co-founded the group Right to Vote.[29]

Gyimah has been married to Dr Nicky Black since 2012, with whom he has a son and a daughter.[1][7]

Gyimah has been a volunteer and fundraiser for Crisis, the Down's Syndrome Association and St. Catherine's Hospice in Surrey. He has served as school governor of an inner London school, on the board of a housing association and on the development board of Somerville College. He is a Vice-President of the Young Epilepsy charity (formerly the National Centre for Young People with Epilepsy (NCYPE) in Lingfield.[1]